Move statistics request methods into NodeStatisticsHandler
[controller.git] / opendaylight / md-sal / statistics-manager / src / main / java / org / opendaylight / controller / md / statistics / manager / StatisticsProvider.java
index b7fb4e9473f740a842d190dec7f916bd4eaa7c33..9ab1e9c5d1a453a4fc24746a96d2862e5db620a9 100644 (file)
@@ -8,13 +8,13 @@
 package org.opendaylight.controller.md.statistics.manager;
 
 import java.util.Collection;
-import java.util.List;
+import java.util.Timer;
+import java.util.TimerTask;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
 
-import org.opendaylight.controller.md.statistics.manager.MultipartMessageManager.StatsRequestType;
 import org.opendaylight.controller.sal.binding.api.NotificationProviderService;
 import org.opendaylight.controller.sal.binding.api.RpcConsumerRegistry;
 import org.opendaylight.controller.sal.binding.api.data.DataBrokerService;
@@ -26,50 +26,26 @@ import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.Fl
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.meters.Meter;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.Table;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.Flow;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.statistics.rev130819.GetAggregateFlowStatisticsFromFlowTableForAllFlowsInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.statistics.rev130819.GetAggregateFlowStatisticsFromFlowTableForAllFlowsOutput;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.statistics.rev130819.GetAllFlowsStatisticsFromAllFlowTablesInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.statistics.rev130819.GetAllFlowsStatisticsFromAllFlowTablesOutput;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.statistics.rev130819.GetFlowStatisticsFromFlowTableInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.statistics.rev130819.GetFlowStatisticsFromFlowTableOutput;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.statistics.rev130819.OpendaylightFlowStatisticsService;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.table.statistics.rev131215.GetFlowTablesStatisticsInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.table.statistics.rev131215.GetFlowTablesStatisticsOutput;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.table.statistics.rev131215.OpendaylightFlowTableStatisticsService;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.port.rev130925.queues.Queue;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.queue.rev130925.QueueId;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.group.statistics.rev131111.GetAllGroupStatisticsInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.group.statistics.rev131111.GetAllGroupStatisticsOutput;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.group.statistics.rev131111.GetGroupDescriptionInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.group.statistics.rev131111.GetGroupDescriptionOutput;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.group.statistics.rev131111.OpendaylightGroupStatisticsService;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.Group;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeConnectorId;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeId;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeRef;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.Nodes;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.node.NodeConnector;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.NodeKey;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.meter.statistics.rev131111.GetAllMeterConfigStatisticsInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.meter.statistics.rev131111.GetAllMeterConfigStatisticsOutput;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.meter.statistics.rev131111.GetAllMeterStatisticsInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.meter.statistics.rev131111.GetAllMeterStatisticsOutput;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.meter.statistics.rev131111.OpendaylightMeterStatisticsService;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.port.statistics.rev131214.GetAllNodeConnectorsStatisticsInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.port.statistics.rev131214.GetAllNodeConnectorsStatisticsOutput;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.port.statistics.rev131214.OpendaylightPortStatisticsService;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.queue.statistics.rev131216.GetAllQueuesStatisticsFromAllPortsInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.queue.statistics.rev131216.GetAllQueuesStatisticsFromAllPortsOutput;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.queue.statistics.rev131216.GetQueueStatisticsFromGivenPortInputBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.queue.statistics.rev131216.GetQueueStatisticsFromGivenPortOutput;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.queue.statistics.rev131216.OpendaylightQueueStatisticsService;
 import org.opendaylight.yangtools.concepts.ListenerRegistration;
 import org.opendaylight.yangtools.concepts.Registration;
 import org.opendaylight.yangtools.yang.binding.DataObject;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 import org.opendaylight.yangtools.yang.binding.NotificationListener;
-import org.opendaylight.yangtools.yang.common.RpcResult;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -88,15 +64,13 @@ import com.google.common.base.Preconditions;
  *
  */
 public class StatisticsProvider implements AutoCloseable {
-    public static final int STATS_THREAD_EXECUTION_TIME= 15000;
+    public static final long STATS_COLLECTION_MILLIS = TimeUnit.SECONDS.toMillis(15);
 
     private static final Logger spLogger = LoggerFactory.getLogger(StatisticsProvider.class);
 
-    private final MultipartMessageManager multipartMessageManager = new MultipartMessageManager();
-    private final DataProviderService dps;
-
-    //Local caching of stats
     private final ConcurrentMap<NodeId, NodeStatisticsHandler> handlers = new ConcurrentHashMap<>();
+    private final Timer timer = new Timer("statistics-manager", true);
+    private final DataProviderService dps;
 
     private OpendaylightGroupStatisticsService groupStatsService;
 
@@ -112,19 +86,10 @@ public class StatisticsProvider implements AutoCloseable {
 
     private StatisticsUpdateHandler statsUpdateHandler;
 
-    private Thread statisticsRequesterThread;
-
-    private Thread statisticsAgerThread;
-
-
     public StatisticsProvider(final DataProviderService dataService) {
         this.dps = Preconditions.checkNotNull(dataService);
     }
 
-    public MultipartMessageManager getMultipartMessageManager() {
-        return multipartMessageManager;
-    }
-
     private final StatisticsListener updateCommiter = new StatisticsListener(StatisticsProvider.this);
 
     private Registration<NotificationListener> listenerRegistration;
@@ -147,55 +112,34 @@ public class StatisticsProvider implements AutoCloseable {
         // Register for switch connect/disconnect notifications
         final InstanceIdentifier<FlowCapableNode> fcnId = InstanceIdentifier.builder(Nodes.class)
                 .child(Node.class).augmentation(FlowCapableNode.class).build();
+        spLogger.debug("Registering FlowCapable tracker to {}", fcnId);
         this.flowCapableTrackerRegistration = dbs.registerDataChangeListener(fcnId,
                 new FlowCapableTracker(this, fcnId));
 
         statsUpdateHandler = new StatisticsUpdateHandler(StatisticsProvider.this);
         registerDataStoreUpdateListener(dbs);
 
-        statisticsRequesterThread = new Thread( new Runnable(){
-
+        timer.schedule(new TimerTask() {
             @Override
             public void run() {
-                while(true){
-                    try {
-                        statsRequestSender();
-
-                        Thread.sleep(STATS_THREAD_EXECUTION_TIME);
-                    }catch (Exception e){
-                        spLogger.error("Exception occurred while sending stats request : {}",e);
+                try {
+                    // Send stats requests
+                    for (NodeStatisticsHandler h : handlers.values()) {
+                        h.requestPeriodicStatistics();
                     }
-                }
-            }
-        });
-
-        spLogger.debug("Statistics requester thread started with timer interval : {}",STATS_THREAD_EXECUTION_TIME);
-
-        statisticsRequesterThread.start();
 
-        statisticsAgerThread = new Thread( new Runnable(){
-
-            @Override
-            public void run() {
-                while(true){
-                    try {
-                        for(NodeStatisticsHandler nodeStatisticsAger : handlers.values()){
-                            nodeStatisticsAger.cleanStaleStatistics();
-                        }
-                        multipartMessageManager.cleanStaleTransactionIds();
-
-                        Thread.sleep(STATS_THREAD_EXECUTION_TIME);
-                    }catch (Exception e){
-                        spLogger.error("Exception occurred while sending stats request : {}",e);
+                    // Perform cleanup
+                    for(NodeStatisticsHandler nodeStatisticsAger : handlers.values()){
+                        nodeStatisticsAger.cleanStaleStatistics();
                     }
+
+                } catch (RuntimeException e) {
+                    spLogger.warn("Failed to request statistics", e);
                 }
             }
-        });
-
-        spLogger.debug("Statistics ager thread started with timer interval : {}",STATS_THREAD_EXECUTION_TIME);
-
-        statisticsAgerThread.start();
+        }, 0, STATS_COLLECTION_MILLIS);
 
+        spLogger.debug("Statistics timer task with timer interval : {}ms", STATS_COLLECTION_MILLIS);
         spLogger.info("Statistics Provider started.");
     }
 
@@ -234,218 +178,32 @@ public class StatisticsProvider implements AutoCloseable {
         return dps.beginTransaction();
     }
 
-    private void statsRequestSender() {
-        for (NodeStatisticsHandler h : handlers.values()) {
-            sendStatisticsRequestsToNode(h.getTargetNodeKey());
+    public void sendFlowStatsFromTableRequest(NodeKey node, Flow flow) throws InterruptedException, ExecutionException {
+        final NodeStatisticsHandler h = getStatisticsHandler(node.getId());
+        if (h != null) {
+            h.sendFlowStatsFromTableRequest(flow);
         }
     }
 
-    private void sendStatisticsRequestsToNode(NodeKey targetNode){
-
-        spLogger.debug("Send requests for statistics collection to node : {})",targetNode.getId());
-
-        InstanceIdentifier<Node> targetInstanceId = InstanceIdentifier.builder(Nodes.class).child(Node.class,targetNode).toInstance();
-
-        NodeRef targetNodeRef = new NodeRef(targetInstanceId);
-
-        try{
-            if(flowStatsService != null){
-                sendAggregateFlowsStatsFromAllTablesRequest(targetNode);
-                sendAllFlowsStatsFromAllTablesRequest(targetNodeRef);
-            }
-            if(flowTableStatsService != null){
-                sendAllFlowTablesStatisticsRequest(targetNodeRef);
-            }
-            if(portStatsService != null){
-                sendAllNodeConnectorsStatisticsRequest(targetNodeRef);
-            }
-            if(groupStatsService != null){
-                sendAllGroupStatisticsRequest(targetNodeRef);
-                sendGroupDescriptionRequest(targetNodeRef);
-            }
-            if(meterStatsService != null){
-                sendAllMeterStatisticsRequest(targetNodeRef);
-                sendMeterConfigStatisticsRequest(targetNodeRef);
-            }
-            if(queueStatsService != null){
-                sendAllQueueStatsFromAllNodeConnector (targetNodeRef);
-            }
-        }catch(Exception e){
-            spLogger.error("Exception occured while sending statistics requests : {}", e);
+    public void sendGroupDescriptionRequest(NodeKey node) throws InterruptedException, ExecutionException{
+        final NodeStatisticsHandler h = getStatisticsHandler(node.getId());
+        if (h != null) {
+            h.sendGroupDescriptionRequest();
         }
     }
 
-
-    private void sendAllFlowTablesStatisticsRequest(NodeRef targetNodeRef) throws InterruptedException, ExecutionException {
-        final GetFlowTablesStatisticsInputBuilder input =
-                new GetFlowTablesStatisticsInputBuilder();
-
-        input.setNode(targetNodeRef);
-
-        Future<RpcResult<GetFlowTablesStatisticsOutput>> response =
-                flowTableStatsService.getFlowTablesStatistics(input.build());
-
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNodeRef),response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_FLOW_TABLE);
-
-    }
-
-    private void sendAllFlowsStatsFromAllTablesRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
-        final GetAllFlowsStatisticsFromAllFlowTablesInputBuilder input =
-                new GetAllFlowsStatisticsFromAllFlowTablesInputBuilder();
-
-        input.setNode(targetNode);
-
-        Future<RpcResult<GetAllFlowsStatisticsFromAllFlowTablesOutput>> response =
-                flowStatsService.getAllFlowsStatisticsFromAllFlowTables(input.build());
-
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_FLOW);
-
-    }
-
-    public void sendFlowStatsFromTableRequest(NodeRef targetNode,Flow flow) throws InterruptedException, ExecutionException{
-        final GetFlowStatisticsFromFlowTableInputBuilder input =
-                new GetFlowStatisticsFromFlowTableInputBuilder();
-
-        input.setNode(targetNode);
-        input.fieldsFrom(flow);
-
-        Future<RpcResult<GetFlowStatisticsFromFlowTableOutput>> response =
-                flowStatsService.getFlowStatisticsFromFlowTable(input.build());
-
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_FLOW);
-
-    }
-
-    private void sendAggregateFlowsStatsFromAllTablesRequest(final NodeKey nodeKey) throws InterruptedException, ExecutionException{
-        FlowCapableNode node = (FlowCapableNode)dps.readOperationalData(
-                InstanceIdentifier.builder(Nodes.class).child(Node.class,nodeKey).augmentation(FlowCapableNode.class).build());
-        if (node != null) {
-            final List<Table> tables = node.getTable();
-            if (tables != null) {
-                spLogger.debug("Node {} supports {} table(s)", nodeKey, tables.size());
-                for(Table table : tables) {
-                    sendAggregateFlowsStatsFromTableRequest(nodeKey, table.getId());
-                }
-            } else {
-                spLogger.debug("Node {} has no associated tables", nodeKey);
-            }
-        } else {
-            spLogger.debug("Node {} not found", nodeKey);
+    public void sendMeterConfigStatisticsRequest(NodeKey node) throws InterruptedException, ExecutionException {
+        final NodeStatisticsHandler h = getStatisticsHandler(node.getId());
+        if (h != null) {
+            h.sendMeterConfigStatisticsRequest();
         }
     }
 
-    private void sendAggregateFlowsStatsFromTableRequest(NodeKey targetNodeKey,Short tableId) throws InterruptedException, ExecutionException{
-
-        spLogger.debug("Send aggregate stats request for flow table {} to node {}",tableId,targetNodeKey);
-        GetAggregateFlowStatisticsFromFlowTableForAllFlowsInputBuilder input =
-                new GetAggregateFlowStatisticsFromFlowTableForAllFlowsInputBuilder();
-
-        input.setNode(new NodeRef(InstanceIdentifier.builder(Nodes.class).child(Node.class, targetNodeKey).toInstance()));
-        input.setTableId(new org.opendaylight.yang.gen.v1.urn.opendaylight.table.types.rev131026.TableId(tableId));
-        Future<RpcResult<GetAggregateFlowStatisticsFromFlowTableForAllFlowsOutput>> response =
-                flowStatsService.getAggregateFlowStatisticsFromFlowTableForAllFlows(input.build());
-
-        multipartMessageManager.setTxIdAndTableIdMapEntry(targetNodeKey.getId(), response.get().getResult().getTransactionId(), tableId);
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(targetNodeKey.getId(), response.get().getResult().getTransactionId()
-                , StatsRequestType.AGGR_FLOW);
-    }
-
-    private void sendAllNodeConnectorsStatisticsRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
-
-        final GetAllNodeConnectorsStatisticsInputBuilder input = new GetAllNodeConnectorsStatisticsInputBuilder();
-
-        input.setNode(targetNode);
-
-        Future<RpcResult<GetAllNodeConnectorsStatisticsOutput>> response =
-                portStatsService.getAllNodeConnectorsStatistics(input.build());
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_PORT);
-
-    }
-
-    private void sendAllGroupStatisticsRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
-
-        final GetAllGroupStatisticsInputBuilder input = new GetAllGroupStatisticsInputBuilder();
-
-        input.setNode(targetNode);
-
-        Future<RpcResult<GetAllGroupStatisticsOutput>> response =
-                groupStatsService.getAllGroupStatistics(input.build());
-
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_GROUP);
-
-    }
-
-    public void sendGroupDescriptionRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
-        final GetGroupDescriptionInputBuilder input = new GetGroupDescriptionInputBuilder();
-
-        input.setNode(targetNode);
-
-        Future<RpcResult<GetGroupDescriptionOutput>> response =
-                groupStatsService.getGroupDescription(input.build());
-
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.GROUP_DESC);
-
-    }
-
-    private void sendAllMeterStatisticsRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
-
-        GetAllMeterStatisticsInputBuilder input = new GetAllMeterStatisticsInputBuilder();
-
-        input.setNode(targetNode);
-
-        Future<RpcResult<GetAllMeterStatisticsOutput>> response =
-                meterStatsService.getAllMeterStatistics(input.build());
-
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_METER);;
-
-    }
-
-    public void sendMeterConfigStatisticsRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
-
-        GetAllMeterConfigStatisticsInputBuilder input = new GetAllMeterConfigStatisticsInputBuilder();
-
-        input.setNode(targetNode);
-
-        Future<RpcResult<GetAllMeterConfigStatisticsOutput>> response =
-                meterStatsService.getAllMeterConfigStatistics(input.build());
-
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.METER_CONFIG);;
-
-    }
-
-    private void sendAllQueueStatsFromAllNodeConnector(NodeRef targetNode) throws InterruptedException, ExecutionException {
-        GetAllQueuesStatisticsFromAllPortsInputBuilder input = new GetAllQueuesStatisticsFromAllPortsInputBuilder();
-
-        input.setNode(targetNode);
-
-        Future<RpcResult<GetAllQueuesStatisticsFromAllPortsOutput>> response =
-                queueStatsService.getAllQueuesStatisticsFromAllPorts(input.build());
-
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_QUEUE_STATS);;
-
-    }
-
-    public void sendQueueStatsFromGivenNodeConnector(NodeRef targetNode,NodeConnectorId nodeConnectorId, QueueId queueId) throws InterruptedException, ExecutionException {
-        GetQueueStatisticsFromGivenPortInputBuilder input = new GetQueueStatisticsFromGivenPortInputBuilder();
-
-        input.setNode(targetNode);
-        input.setNodeConnectorId(nodeConnectorId);
-        input.setQueueId(queueId);
-        Future<RpcResult<GetQueueStatisticsFromGivenPortOutput>> response =
-                queueStatsService.getQueueStatisticsFromGivenPort(input.build());
-
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_QUEUE_STATS);;
-
+    public void sendQueueStatsFromGivenNodeConnector(NodeKey node,NodeConnectorId nodeConnectorId, QueueId queueId) throws InterruptedException, ExecutionException {
+        final NodeStatisticsHandler h = getStatisticsHandler(node.getId());
+        if (h != null) {
+            h.sendQueueStatsFromGivenNodeConnector(nodeConnectorId, queueId);
+        }
     }
 
     /**
@@ -464,25 +222,18 @@ public class StatisticsProvider implements AutoCloseable {
         return handler;
     }
 
-    @SuppressWarnings("unchecked")
-    private NodeId getNodeId(NodeRef nodeRef){
-        InstanceIdentifier<Node> nodeII = (InstanceIdentifier<Node>) nodeRef.getValue();
-        NodeKey nodeKey = InstanceIdentifier.keyOf(nodeII);
-        return nodeKey.getId();
-    }
-
     @Override
     public void close() {
         try {
             if (this.listenerRegistration != null) {
                 this.listenerRegistration.close();
-                this.statisticsRequesterThread.destroy();
-                this.statisticsAgerThread.destroy();
+                this.listenerRegistration = null;
             }
             if (this.flowCapableTrackerRegistration != null) {
                 this.flowCapableTrackerRegistration.close();
                 this.flowCapableTrackerRegistration = null;
             }
+            timer.cancel();
         } catch (Exception e) {
             spLogger.warn("Failed to stop Statistics Provider completely", e);
         } finally {
@@ -490,23 +241,27 @@ public class StatisticsProvider implements AutoCloseable {
         }
     }
 
-    synchronized void startNodeHandlers(final Collection<NodeKey> addedNodes) {
+    void startNodeHandlers(final Collection<NodeKey> addedNodes) {
         for (NodeKey key : addedNodes) {
             if (handlers.containsKey(key.getId())) {
                 spLogger.warn("Attempted to start already-existing handler for {}, very strange", key.getId());
                 continue;
             }
 
-            final NodeStatisticsHandler h = new NodeStatisticsHandler(this, key);
-            handlers.put(key.getId(), h);
-            spLogger.debug("Started node handler for {}", key.getId());
-
-            // FIXME: this should be in the NodeStatisticsHandler itself
-            sendStatisticsRequestsToNode(key);
+            final NodeStatisticsHandler h = new NodeStatisticsHandler(dps, key,
+                    flowStatsService, flowTableStatsService, groupStatsService,
+                    meterStatsService, portStatsService, queueStatsService);
+            final NodeStatisticsHandler old = handlers.putIfAbsent(key.getId(), h);
+            if (old == null) {
+                spLogger.debug("Started node handler for {}", key.getId());
+                h.start();
+            } else {
+                spLogger.debug("Prevented race on handler for {}", key.getId());
+            }
         }
     }
 
-    synchronized void stopNodeHandlers(final Collection<NodeKey> removedNodes) {
+    void stopNodeHandlers(final Collection<NodeKey> removedNodes) {
         for (NodeKey key : removedNodes) {
             final NodeStatisticsHandler s = handlers.remove(key.getId());
             if (s != null) {